Lecture 5 Flashcards
What might be the reasons as to why sickness behaviours exist?
Innate immune stimuli have aversive properties
By-product of metabolic constraints for mounting a fever
Non-specific adaptive immune response to stimulation
Expression of a central motivational state
Part of a pain defense system
What is the evidence that inflammatory pathways are activated in patients with major depression?
Increased pro-inflammatory cytokines
Increased acute phase proteins
Increased expression of chemokines and adhesion molecules
Increased serum IL-6 and C reactive protein
Increased IL-1Beta and TNFalpha in CSF
Functional allelic variants of IL-1Beta and TNFalpha genes increase the risk of depression
What was observed in melanoma patients who were treated with interferon?
It was found that those who developed depressive symptoms had an activated HPA axis with increased levels of cortisol and ACTH compared with to those who recieved same treatment but did not developed symptoms
What was the experiment performed by eisenberger in 2012?
39 healthy participants were taken and injected with either a placebo or endotoxin and had their blood measurements taken hourly from an inserted catheter with temperature, pulse, blood pressure recorded half hourly for 6 hours along with hourly assessments of symptoms and moods
What conclusions were reached by eisenberger and et als. Expermiment?
Endotoxin was found to lead to significant increases in IL-6 and TNF-alpha levels, fellings of social disconnection and a general depressed mood
however controlling for increases in social disconnection eliminated the relationship between endotoxin challenge and the depressed mood
This implies that inflammatiom may have social psychological consequences and could play a role in cytokine-related depressive symptoms
What happens in hepatitis C patients who are treated with IFN-alpha and Ribavirin?
It was found that increases in depressive symptoms correlated with poor clearancd of the Hep C virus
What is the clinical definition of major depression?
5 of the following symptoms Depressed mood Anhedonia Fatigue Guilt and/or worthlessness Suicidal ideation Impaired concentration and/or memory Psychomotor retardation and/or agitation Disturbances of sleep or appetite These must persist for at least 2 weeks and cause significant functional impairment
What is the suggested link between immune activation and depression?
In 1993 Psychiatry created the macrophage theory of depression, which was supported and built on by psychoneurimmune literature which made the link between sickness behaviour and depression in 1999
These converged on the idea that chronic immune activation is associated with depression and was supported by studys looking at immunotherapy for cancer and hepatitis treatment, somatic disorders where there is an inflammatory component and ageing
